Computers Having a Biometric Authentication Device

1. A method comprising: placing a portable computer in an non-operating state, wherein said portable computer includes a start-up button, a proximity sensor, a biometric authentication device, a power supply unit containing a first power system and a second power system capable of having less power loss than said first power system in a light-load condition; deactivating said second power system so that electric power is supplied from said first power system to said biometric authentication device during said non-operating state of said portable computer; in response to said proximity sensor's detection of a person being proximate to said biometric authentication device, activating said second power system so that electric power is supplied from said second power system to said biometric authentication device during said non-operating state of said portable computer; performing an authentication operation while receiving electric power from said second power system during said non-operating state of said portable computer; and in response to said authentication operation being a success, starting up said portable computer by causing said portable computer to transition from said non-operating state to a power-on state.

2. The method of claim 1 , wherein said starting up further includes generating a pseudo startup signal equivalent to a startup signal generated by a depression of said start-up button.

3. The method of claim 2 , wherein said placing further includes transition said portable computer to a power-off (DC) state where it is possible to supply electric power to said portable computer solely by a battery.

4. The method of claim 1 , wherein said activating is performed in a state of ensuring uninterrupted power supply by supplying electric power from any one of said first and said second power systems when switching from said first power system to said second power system.

5. The method of claim 3 , wherein said method further includes sending a command that asserts physical presence to a security chip in response to the generation of said pseudo startup signal, during one of a hibernation state, a power-off (AC) state where electric power is supplied by an AC/DC adapter, and a power-off (DC) state where electric power is solely supplied by said battery.

6. The method of claim 5 , wherein said method further includes sending a command that contradicts said physical presence to said security chip in response to the generation of said pseudo startup signal in a suspended state.

7. The method of claim 5 , wherein said method further includes executing single sign-on with respect to a power-on password, a supervisor password, and a hard disk drive password in response to said sending command that asserts physical presence to said security chip.

8. The method of claim 1 , wherein said method further includes displaying failure in said authentication in response an authentication failure.

9. A portable computer comprising: a processor; a proximity sensor; a power supply unit having a first power system and a second power system capable of having less power loss in a light-load condition than said first power system; a power control circuit for controlling said power supply unit; a start-up button for generating a startup signal for starting said portable computer; and a biometric authentication device for generating and sending a power request signal to said power control circuit to activate said second power system upon said proximity sensor's detection of a person being proximate to said biometric authentication device when said second power system is deactivated and electric power is being supplied by said first power system, wherein said biometric authentication device performs an authentication operation while receiving electric power from said second power system during a non-operating state of said portable wherein said power control circuit causes said portable computer to transition from said non-operating state to a power-on state in response to an authentication success by said biometric authentication device.

10. The portable computer of claim 9 , wherein said biometric authentication device sends a pseudo startup signal to said power control circuit after said authentication success.

11. The portable computer of claim 9 , wherein said portable computer transitions to a power-off (DC) state where it is supplied with electric power solely by said battery when said biometric authentication device detects a person swiping a finger on said biometric sensor in a state of being supplied with electric power from said first power system.

12. The portable computer of claim 9 , wherein said first power system is configured by a linear regulator, and said second power system is configured by a switching regulator.

13. The portable computer of claim 9 , further comprising a switching circuit for switching power source of said biometric authentication device from said first power system to said second power system.

14. The portable computer of claim 13 , wherein said switching circuit is configured by a first FET is connected to said first power system and said biometric authentication device, a diode connected in parallel to said first FET, and a second FET connected to said second power system and said biometric authentication device.

15. The portable computer of claim 9 , further comprising an indicator for displaying an authentication failure.

16. The portable computer of claim 10 , further comprising a security chip; and a nonvolatile memory storing a CRTM authentication code, wherein said processor executes said CRTM authentication code before said pseudo startup signal is generated and an operating system sends a command that asserts physical presence to said security chip when said portable computer is being cold-started.

17. The portable computer of claim 16 , wherein said processor permits a single sign-on with respect to a power-on password, a supervisor password, and a hard disk drive password when said command that asserts physical presence has been sent to said security chip.

18. The portable computer of claim 9 , wherein said biometric authentication device is a fingerprint authentication device.